I suspect reality will be somewhere between Pournelle's "Lucifer's Hammer" and "The Postman." NO WAY Hollywood would let stuff like that out this close to an election without the RATs screaming holy heck.
People spontaneously packed the churches on the night of 9/11/01. I visited several services and it was the same at every church I saw.
Hollyweird won't get this right. Not in today's political climate.
A cold war exchange of nukes would have been mutually assured destruction - each side dropping hundreds, if not thousands of nukes...
Today it's different.
With rogue states and nutty bands of terrorists, it'll be a nuke here - or there - but not doomsday.
People can survive if they have good information. Information is the difference between being on a plane flown into the Twin Towers and being on Flight 93. Forewarned is forearmed.
So, Jerico seemed scary. It looked like someone was trying to give us information to save our lives. Well, up until they had the kid drink iodine. That'll kill a person. And the talk about if you vomit after being exposed to radiation being a sure sign of death? Not always. Some will vomit and get better - depending on dosage, and some will vomit and die... That should have been clarified.
So Jerico is entertainment - not a way to educate the public for an imminent attack - and with that thought - it quit being so scary...and so interesting....